نتایج جستجو برای: apatite
تعداد نتایج: 3601 فیلتر نتایج به سال:
Recent solubility, electrokinetic, spectroscopic and flotation studies in our laboratory on apatite and calcite in aqueous electrolytes indicate complex mineral_olution interactions which can alter surface characteristics of these minerals markedly in the presence of each other. In the case of systems containing such sparingly soluble minerals, understanding of the mineral_olution chemical equi...
Mineral weathering in soils is an important source of many nutrients to forest ecosystems. Apatite, a Ca phosphate mineral, occurs in trace amounts in virtually all igneous and metamorphic rocks and is often found as small mineral inclusions in more weathering-resistant silicate minerals. To better understand the distribution of apatite in soils and its exposure to soil solutions, a sequential ...
This paper describes the apatite deposition of chitosan-silicate porous hybrids derived from chitosan and γ-glycidoxypropyltrimethoxysilane (GPTMS) in alkaline phosphate solution. The preparation of porous hybrids with needle-like apatite on their surfaces is described. Following apatite deposition the porous hybrids maintained high porosity. The enzymatic degradation rate was low even after 6 ...
The particle size of apatite is one of the critical factors that influence the adsorption of heavy metals on apatite in the remediation of heavy metal contaminated soils using apatite. However, little research has been done evaluating the impact of different particle sizes of apatite on immobilization remediation of heavy metal polluted soils in field. In this study, the adsorption isothermal e...
Porous bioactive glasses are attractive for use as bone scaffolds. There is increasing interest in strontium containing bone grafts, since strontium ions are known to up-regulate osteoblasts and down regulate osteoclasts. This paper investigates the influence of partial to full substitution of strontium for calcium on the dissolution and phase formation of a multicomponent high phosphate conten...
this research was conducted at the department of horticluture, university of tehran during years 2005-2006, to investigate the use of iran apatite rocks in zeoponic substrate and as well to evaluate them as substitutes for phosphate fertilizers. five different substrates namely: m1: 89 wt. % soil+10 wt. % zeolite + 1 wt.% jeyrood apatite; m2: 82 wt.% soil + 15 wt.% zeolite+ 3 wt. % jeyrood apat...
The Lakeh-Siah iron± apatite deposit is located in the Bafq-Saghand Metallogenic Province (Central Iran) and situated within rhyolitic rocks. Magnetite with minor apatite are the main ore minerals in this deposit. Monazite and xenotime minerals in microscopic scale formed as inclusion in the apatite and magnetite crystals and micro-fractures. Based on microscopic and EPMA evidences, apatite is ...
We present compositions, including REEs determined by ion microprobe, of apatite and whitlockite in lunar rock assemblages rich in incompatible trace elements. Total concentrations of REE oxides in whitlockites range from 9-13 wt%, and those in apatites range from 0.15 to 1 wt%. Ratios of REE concentrations in whitlockite to those in coexisting apatite range from 10 to 60. The distribution of M...
In this study, we investigated a novel method for fabrication of carbonate apatite block without ionic movement between precursor and solution by using precursor that includes all constituent ions of carbonate apatite. A powder mixture prepared from dicalcium phosphate anhydrous and calcite at appropriate Ca/P ratios (1.5, 1.67, and 1.8) was used as starting material. For preparation of specime...
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